Pushbutton switch latching mechanism

ABSTRACT

An alternate action pushbutton switch includes a plunger which is movable between latch and release positions. The switch associated with the plunger is only operated when the plunger has been committed to a latch position.

United States Patent [191 Van Benschoten PUSHBUTTON SWITCH LATCHINGMECHANISM Peter J. Van Benschoten, Rancho Santa Fe, Calif.

Oak Industries, Inc., Crystal Lake, Ill

Inventor:

Assignee:

Filed: Feb. 8, 1973 Appl. No.: 330,574

US. Cl. 200/153 J, 200/169 PB Int. Cl. I'I0lh 13/56 Field of Search200/153 J, 169 PB References Cited UNITED STATES PATENTS 10/1960 Ensign,Jr, et ul. ZOO/I53 J X June 28, 1974 3,153,714 lO/l964 Bury 200/153 J X3,3 l2,805 4/ l 967 Bury 3,624,328 ll/l971 Hansen 200/153 J FOREIGNPATENTS OR APPLICATIONS 958,664 5/l964 Great Britain ZOO/I53 J PrimaryExaminerRobert K. Schaefer Assistant Examiner-William J. Smith Attorney,Agent, or Firm-Kinzer, Plyer, Dom & McEachran [57] ABSTRACT An alternateaction pushbutton switch includes a plunger which is movable betweenlatch and release positions. The switch associated with the plunger isonly operated when the plunger has been committed to a latch position.

11 Claims, 7 Drawing Figures PATENTED JUN 2 8 I974 SHEET 1 BF 2PUSHBUTTON SWITCH LATCHING MECHANISM SUMMARY OF THE INVENTION Thepresent invention relates to a push to latch and push to release switcharrangement and is particularly directed to such an alternate actiontype of switch in which switching cannot be accomplished unless thelatching operation is performed simultaneously therewith. r

A primary purpose of the invention is a switch of the type described inwhich there can be no operation of the switch without latching of theplunger.

Another purpose is in an alternate action type of switch mechanism usingfewer parts than previous mechanisms of the same general type.

Another purpose is in an alternate action type of switch of the typedescribed requiring substantially reduced assembly time over previousconstructions.

Another purpose is a push to latch and push to re lease switch utilizinga pivotal latch member and a pivotal actuator which are in directcontact with each other.

Another purpose is a switching mechanism of the type described in whicha common spring provides the force for the actuator to operate theswitch and urges the latch member into contact with the plunger cam.

Other purposes will appear in the ensuing specification, drawings andclaims.

BRIEF DESCRIPTION OF THE DRAWINGS The invention is illustrateddiagrammatically in the following drawings wherein:

FIG. I is a front view with portions in section of the switch mechanism;

FIG. 2 is a partial side view in section of the switch mechanism;

FIG. 3 is a partial front view, similar to FIG. 1, showing the mechanismin a latched position;

FIG. 4 is a partial side view, similar to FIG. 2, showing the mechanismin a latched position;

FIG. 5 is a top view of the switch plunger;

FIG. 6 is a section along plane 6-6 of FIG. 5; and

FIG. 7 is a section along plane 7-7 of FIG. 3.

DESCRIPTION OF THE PREFERRED EMBODIMENT A popular type of alternateaction switch uses a latching mechanism to hold the pushbutton in adepressed position until the button is released by a second operation.This type of switch gives a positive visual indication of the on-offcondition due to the differences in pushbutton positions. In the pastlatching mecha nisms have been of a kind where when the pushbutton hasbeen depressed sufficiently, releasing it will cause it to latch.However, when such a mechanism is used in conjunction with switchcontacts it is necessary that the contacts be connected substantiallybefore the latch position is reached, to assure the switch is always inthe on condition whenever the pushbutton is latched down. The majordrawback of this type of mechanism is that it is possible to depress thepushbutton to the point where the switch closes but not far enough tocause it to latch when the button is released. When this happens thebutton will return to the off position and the switch will open. Thistype of operation can be disconcerting to theoperator, particularlywhere high power levels are involved. Such fast on-off operation canshorten switch life, blow fuses and damage electrical components.

The present invention provides a switching mechanism of the typedescribed in which the electrical switching operation cannot take placeuntil the pushbutton has been committed to move to a latching positron.

In the drawings, a housing is indicated generally at 10 and may includean upper housing section 12 and a lower housing section 14. Mountedwithin the housing is a plunger 16 which may be reciprocally movedbetween the latch and release positions indicated in FIGS. 3 and 1respectively. At the upper end of the plunger 16 is a lens 18 containinga suitable light bulb or the like 20.

Within the lower housing section 14 is a switch assembly 22 having anoperating button 24 extending upwardly therefrom. Positioned above theswitch assembly 22 is an actuator 26, the opposite sides of which arepivotally mounted on rods 28 fixed in opposite side walls of the housing14.

A latch member or latch wire is indicated at 30 and has an inwardlydirected end 32 which cooperates with a generally heart-shaped cam 34fonned on one side of the plunger 16. The lower end of the latch wire30, indicated at 36 is pivotally mounted to actuator 26 by spacedintegral rings 38 and 42 on the actuator. The latch wire is pivotallymovable on the actuator and the actuator is pivotally movable relativeto the housing section 14. A latch spring 40 has its lower end mountedon ring 42 of the actuator and has its upper end mounted within theplunger as described hereinafter. The latch spring 40 biases the latchwire end section 32 into frictional contact with the cam 34 and alsobiases the actuator toward the switch operator 24.

The plunger 16 has downwardly directed feet 44 which contact the switchassembly 22 when the plunger has been moved to its fully depressedposition. The feet 44 accordingly provide an inward stop for plungermovement. The bottom surface of the plunger 16 may have a series ofopenings. One such opening, indicated at 46, receives the upper end ofthe latch spring 40. Openings 48 generally diametrically spaced withinthe plunger receive lamp springs 50, there being a pair of such springswhich are effective to normally bias the plunger to the outward orrelease position shown in FIG. 1.

A pair of lamp terminals are indicated at 52, such terminals beingpositioned within the housing 14 and outside of the switch assembly 22.The lamp terminals 52 have inwardly and upwardly directed portions 54which mount the lamp springs 50. There are connections within theplunger, not shown, which electrically connect the upper end of the lampsprings 50 to suitable contacts for electrically connecting the lamp 20to the lamp terminals 52 when the plunger is in the latch position.

The cam surface 34 on the plunger 16 includes an upwardly inclined ramp55, the lower end of which terminates at the plunger lower surface 56.The upper end of the ramp 55 terminates in a ledge 58 which extends intothe plunger. Above and inside of ledge 58 is a plunger latching area 60.Integral with the ledge 58 is a depression 62 which is formed to receivethe inwardly directed portion 32 of the latch wire when the plunger isin the latched position of FIG. 3. Adjacent to one side of thedepression 62 is a release ramp 64 which leads from the latching area 60outwardly to the inclined ramp 64. The cam 34 has several levels,relative to the latch wire 32. The inclined ramp 55 and the ledge 58define a surface 66, which is inside of the outer surface 67. Above andinward from the ledge 58 is the latching area 60. The release ramp 64connects area 60 and surface 66 through a stop 69 and defines theinternal island or heart-shaped area 68. The stop 69 prevents the latchspring from accidentally passing into ramp 64 when the plunger isdepressed from the outward position.

The release position of the switch assembly is shown in FIGS. 1 and 2.The latch wire holds the actuator in position away from the switchoperator 24. The inwardly directed end 32 of the latch wire 30 is incontact with surface 66 of cam 34 and is held in such frictional contactby the spring 40. As the plunger is depressed the ramp 55 will cause theend 32 of the latch wire 30 to pivot to the left as shown in FIGv 1.Continued downward movement of the plunger will eventually cause thelatch wire to move to the top of the ramp and as the end 32 of the latchwire passes over the ledge 58, the latch wire will be snapped inwardly,to the position of FIG. 4. At this point the plunger is committed to alatching position. Such inward movement of the latch wire 30 permits thecompressed spring to pivot the actuator 26 about the rods 28 such thatthe base of the actuator will cause the switch operator 24 to bedepressed to operate the switch assembly 22. The spring 40 not onlyprovides a bias to insure frictional contact between the latch wire andthe cam surface, but also provides the operating force for the actuator26. The latch wire 30 holds the actuator away from the switch operatoruntil such time as the latch wire end 32 passes over the ledge 58 tocommit the plunger to move to a latching position. Release of theplunger at this point will cause a slight upward movement of the plungeras the latch wire end 32 moves into the depression 62 of the cam 34.

The next operation of the plunger will effect a release of the switchoperator. As the plunger is depressed, surface 70 of the cam willcontact the latch wire end 32 causing the latch wire to pivot to theright. Subsequent release of the plunger, permitting it to move upward,causes the latch wire end to travel through the release ramp 64,returning the latch wire to the position of FIG. 1. As the latch wirereturns to the release position of FIG. 1, the actuator will also returnto its original position as projection 26a on the actuator is in contactwith the latch wire and this interlock causes the actuator to move tothe position of FIGS. 1 and 2.

Of particular advantage is the fact that the actuator cannot effectoperation of the switch operator until latch wire 30 commits the plungerto move to the latch position by pivoting inwardly over the ledge 58.Simultaneously with plunger latching there is insurance that the switchassembly will be operated through the interlock between the latch wireand the actuator. There can be no switch operation unless the plunger iscommitted to move to a latch position.

It is necessary for the end of the latch wire to be in frictionalcontact with the heart-shaped cam and such frictional contact ismaintained by the spring 40. This friction prevents excessive freedom inrotation of the latch wire relative to the cam and relative to theactuator. Note that the lower end of the latch spring presses directlyagainst the latch wire, pressing the latch wire against the actuator.

The number of parts and thus the assembly time have been decreasedsubstantially from prior alternate action switches of this general type.

Whereas the preferred form of the invention has been shown and describedherein, it should be realized that there may be many modifications,substitutions and alterations thereto.

The embodiments of the invention in which an exclusive property orprivelege is claimed are defined as follows:

l. A switching mechanism including a housing, a plunger reciprocallymovable in said housing, a switch assembly positioned in said housing,an actuator in said housing positioned to effect operation of saidswitch assembly,

a latch member positioned in said housing and associated cam means onsaid plunger, yielding means urging said latch member into contact withsaid cam means, said latch member and cam means being arranged toalternately latch and release said lunger as it is reciprocally movedwithin the housmg, said latch member being movable between latch andrelease positions by said cam means and plunger,

means interlocking said latch member and actuator,

including contact there between to prevent movement of the actuatorrelative to the switch assembly until said latch member has moved asufficient distance relative to said cam means to commit said plunger toa latched position, whereby latching of said plunger and actuation ofsaid switch assembly occur simultaneously.

2. The structure of claim 1 further characterized in that said yieldingmeans is in contact with said actuator and is effective to urge saidactuator toward a position to effect operation of said switch assembly.

3. The structure of claim 2 further characterized in that said actuatoris pivotally movable within said housmg.

4. The structure of claim 1 further characterized in that said latchmember pivots while moving between the latch and release position.

5. The structure of claim 4 further characterized in that said actuatoris pivotally mounted within said housing.

6. The structure of claim 6 further characterized in that said yieldingmeans is in contact with said actuator and is effective to apply a forceupon said actuator to effect operation of said switch assembly.

7. The structure of claim 1 further characterized by and includingspring means normally urging said plunger to a release position.

8. The structure of claim 1 further characterized in that said cam meansincludes a ledge, movement of said latch member into said ledge commitssaid plunger to a latching position.

9. The structure of claim 8 further characterized by an including aninclined surface in said cam means leading toward said ledge, movementof said plunger toward a latching position causes said inclined surfaceto move said latch member toward said ledge.

10. The structure of claim 1 further characterized in that said actuatorand latch member are each pivotally mounted within said housing, saidyielding means urging said latch member into contact with said cam meansand being effective to apply a force to urge said actuator toward aposition to effect operation of said switch assembly.

11. The structure of claim 10 further characterized in that said latchmember is pivotally movable on said actuator.

1. A switching mechanism including a housing, a plunger reciprocallymovable in said housing, a switch assembly positioned in said housing,an actuator in said housing positioned to effect operation of saidswitch assembly, a latch member positioned in said housing andassociated cam means on said plunger, yielding means urging said latchmember into contact with said cam means, said latch member and cam meansbeing arranged to alternately latch and release said plunger as it isreciprocally moved within the housing, said latch member being movablebetween latch and release positions by said cam means and plunger, meansinterlocking said latch member and actuator, including contact therebetween to prevent movement of the actuator relaTive to the switchassembly until said latch member has moved a sufficient distancerelative to said cam means to commit said plunger to a latched position,whereby latching of said plunger and actuation of said switch assemblyoccur simultaneously.
 2. The structure of claim 1 further characterizedin that said yielding means is in contact with said actuator and iseffective to urge said actuator toward a position to effect operation ofsaid switch assembly.
 3. The structure of claim 2 further characterizedin that said actuator is pivotally movable within said housing.
 4. Thestructure of claim 1 further characterized in that said latch memberpivots while moving between the latch and release position.
 5. Thestructure of claim 4 further characterized in that said actuator ispivotally mounted within said housing.
 6. The structure of claim 6further characterized in that said yielding means is in contact withsaid actuator and is effective to apply a force upon said actuator toeffect operation of said switch assembly.
 7. The structure of claim 1further characterized by and including spring means normally urging saidplunger to a release position.
 8. The structure of claim 1 furthercharacterized in that said cam means includes a ledge, movement of saidlatch member into said ledge commits said plunger to a latchingposition.
 9. The structure of claim 8 further characterized by anincluding an inclined surface in said cam means leading toward saidledge, movement of said plunger toward a latching position causes saidinclined surface to move said latch member toward said ledge.
 10. Thestructure of claim 1 further characterized in that said actuator andlatch member are each pivotally mounted within said housing, saidyielding means urging said latch member into contact with said cam meansand being effective to apply a force to urge said actuator toward aposition to effect operation of said switch assembly.
 11. The structureof claim 10 further characterized in that said latch member is pivotallymovable on said actuator.